Medical slings

ABSTRACT

A medical sling made from material that is suitably shaped for use in a medical application has sides, portions of which are smoothed to prevent abrasion of surrounding tissue.

This application claims priority to provisional patent application Ser.No. 60/274,843 filed in the U.S. Patent Office on Mar. 9, 2001 andprovisional patent application Ser. No. 60/286,863 filed in the U.S.Patent Office on Apr. 26, 2001, the entire contents of which areincorporated by reference herein.

TECHNICAL FIELD

This invention generally relates to surgical mesh for use as a medicalsling, such as a pelvic floor repair mesh, methods of making such mesh,kits including such mesh, and methods of treating or reinforcing adamaged, prolapsed, weakened or herniated portion of a patient's bodyusing such mesh.

BACKGROUND INFORMATION

Surgical prosthetic mesh has been used to treat or reinforce tissues ororgans which have been damaged, prolapsed, weakened, or otherwiseherniated, such as in the conditions rectocele, cystocele, enterocele,vaginal prolapse, and protocele, for example. A prolapse refers to theslipping down of an organ or organ part from its normal position. Forexample, a prolapse of the rectum refers to the protrusion of the innersurface of the rectum through the anus. Rectocele is the prolapse of therectum into the perineum. A prolapse of the uterus refers to the fallingof the uterus into the vagina due to stretching and laxity of itssupporting structures. Vaginal vault prolapse refers to the prolapse ofthe cephalad extreme of the vaginal canal toward, through, and beyondthe introitus. Cystocele (i.e., vesicocele) is a hernia formed by thedownward and backward displacement of the urinary bladder toward thevaginal orifice, due most commonly to weakening of the musculatureduring childbirth. However, any abnormal descent of the anterior vaginalwall and bladder base at rest or with strain is considered cystocele.Enterocele is a hernia of the intestine, though the term is also used torefer specifically to herniation of the pelvic peritoneum through therectouterine pouch (i.e., posterior vaginal, rectovaginal, cul-de-sac,or Douglas' pouch hernia).

Surgical mesh may also be used to suspend tissues or retract body organstemporarily, e.g., during surgery. For example, U.S. Pat. No. 4,973,300describes the use of a cardiac sling for supporting the heart duringsurgery; and U.S. Pat. No. 5,362,294 describes the retraction of bodyorgans such as the uterus or bowel during laparoscopic surgery; U.S.Pat. No. 6,102,921 describes the use of a medical anastomosis sling forthe use in repair or regeneration of nerves.

Synthetic mesh materials utilized as slings for the treatment orreinforcement of patient tissues for these and many other conditions cancause patient complications such as erosion, due at least in part to thesharp tangs on the edges of the mesh, which are formed during themanufacturing process or afterward (for example, when a physician cutsor shears or otherwise shapes the material). These tangs can cause anirritative effect which can lead to an erosion when they contactsurrounding tissue. Thus, a need exists for a sling which minimizesirritation and erosion of the tissue surrounding the tissue which itsupports.

Stress urinary incontinence (SUI), which primarily affects women, is acondition which is successfully treated using surgical slings. Stressurinary incontinence is generally caused by two conditions that mayoccur independently or in combination, namely, intrinsic sphincterdeficiency (ISD) and hypermobility. In ISD, the urinary sphincter valve,located within the urethra, fails to close properly (coapt), causingurine to leak out of the urethra during stressful actions. Hypermobilityis a condition in which the pelvic floor is distended, weakened ordamaged, causing the bladder neck and proximal urethra to rotate anddescend in response to increases in intra-abdominal pressure (e.g., dueto sneezing, coughing, straining, etc.), resulting in insufficientresponse time to promote urethral closure and, consequently, in urineleakage and/or flow.

Biological factors that can affect hypermobility include: poorendopelvic fascia muscle tone (from age or limited activity), endopelvicfascia muscle stretch/tear from trauma (e.g. childbirth), endopelvicfascia/arcus tendenious (muscle/ligament) separation (lateral defect),hormone deficiency (estrogen), concombinant defects (cystocele,enterocele, ureteral prolapse), and vaginal prolapse. Traditionaltreatment methods include bladder neck stabilization slings in which asling is placed under the urethra or bladder neck to provide a platformpreventing over distention. An emerging alternative treatment is theplacement of a mid-urethral sling. Such a sling placement takesadvantage of the hypermobility condition by providing a fulcrum aboutwhich the urethra and bladder neck will rotate and provide a “urethralkink” to assist normal urethral closure.

Slings are traditionally placed under the bladder neck to provide aurethral platform limiting endopelvic fascia drop while providingcompression to the urethral sphincter to improve coaptation. Themid-urethral placement location provides mechanical stability to a lessmoveable anatomical structure. Bladder neck slings have traditionallybeen affixed in the desired location using a bone anchoring method.Mid-urethral slings, being placed in a low mobility area, havedemonstrated the effectiveness of an anchorless approach. Recognizingthat minimal tension, if any, is necessary, a physician need only placethe sling under the mid-urethra secured through the endopelvic fascia topermanently secure the sling in position. The sling permits immediatetissue security through the mesh openings and mesh tangs to initiallymaintain sling stabilization. As healing occurs, the endopelvic fasciaand rectus fascia tissue re-establish vascularity and regrow into andaround the knit pattern of the mesh. The sling in this procedureprovides a fulcrum about which the pelvic floor will drop (takingadvantage of the hypermobility condition of the patient) and a urethral“kink” or higher resistance to obstruct urine flow during high stressconditions.

Thus, while tangs can contribute beneficially to SUI treatment, they canalso cause patient complications such as erosion of the vagina orurethra.

SUMMARY OF THE INVENTION

The present invention relates to surgical mesh or slings with anon-tanged (i.e., tangs are unformed, smoothed, rounded, or removed)section disposed on a portion of the sides of the mesh, methods ofmaking such mesh, medical kits including such mesh, and methods oftreating a damaged, weakened, sagging, herniated or prolapsed portion ofa patient's body using such mesh.

The benefits of such a sling according to the invention includedecreased tissue irritation from a non-tanged section when it is incontact with tissue, such as urethral and vaginal tissue, whilepromoting rapid scar tissue formation around the tanged portion of thesling. The formation of scar tissue generally adds bulk that compressesthe tissue to which it is applied (e.g., the urethra), provides supportto improve patient continence and inhibits or prevents movement of theplaced sling following placement.

In one aspect, the invention involves a sling for use in a medicalapplication. The sling is made of a mesh material that includes firstand second opposed ends (i.e., disposed opposite and away from eachother) along a longitudinal axis. The mesh material also includes firstand second opposed sides separated by a distance along an axisperpendicular to, or substantially perpendicular to, the longitudinalaxis. The perpendicular axis intersects the longitudinal axis at themidpoint, or substantially at the midpoint, of the perpendicular axis. Aportion of the first and second sides and the first and second ends ofthe material contains tangs. A portion of the first and second sidesdoes not contain tangs (e.g. tangs on the first and second sides areunformed, smoothed, rounded or removed), creating a non-tanged section.The first and second sides may each have, for example, a non-tangedsection about 1 cm to about 5 cm in length, centered along thelongitudinal axis.

The sling of the invention may have a shape suitable for a medicalapplication; e.g., it may be rectangular or substantially rectangular.Alternatively, the sling may be octagonal, hexagonal, trapezoidal,elliptical, or some other shape that is suitable to the sling's intendedplacement location within the body.

In another aspect, the invention relates to a method of making a slingby direct manufacturing with a non-tanged section or by smoothing,rounding or removing the tangs on a portion of the sling to create anon-tanged section.

The sling material provided may be derived from synthetic materials or acombination of mammalian tissue(s) and synthetic material(s). The methodof making the sling can further comprise sterilizing the sling materialaccording to methods known in the art so that the sling is suitable foruse in various medical applications, and may include packaging the slingin a sterile holder. The sling material may be enclosed within a sleeveto assist in handling the sling and/or to adjust the sling duringsurgical placement, or to prevent the sling from stretching or becomingmisshapen due to handling prior to placement within the body of thepatient.

In a further aspect, the invention involves a method of treating adamaged portion of a patient's body using a sling with a non-tangedsection. The sling is placed inside the body of a patient such that itsperpendicular axis lies substantially along a portion of the patient'sbody, such as the mid-urethra, bladder, rectum, vagina, blood vessel,nerve, heart, etc.; the material supports a portion of the patient'sbody in a manner which does not erode the surrounding tissue. The slingmay be centered at the damaged portion of a patient's body using theperpendicular axis of the sling as a guide. Pressure may be distributedevenly on a portion of a patient's body with the secured sling material.A surgical fastener such as a suture, a clip, a bone anchor, a staple,or other suitable fastener, may be employed to secure the sling toanatomical structures.

The sling material may be implanted to treat female urinary incontinenceaccording to transvaginal, transabdominal, or combined transvaginal andtransabdominal procedures. For example, the method may be employed totreat a patient with SUI, the non-tanged section of the sling placedadjacent the patient's mid-urethra.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, but rather illustrate the principles of the invention.

FIG. 1 is a plan view of a rectangular embodiment of a sling having anon-tanged section on either side of the perpendicular axis.

FIG. 2 is a close-up diagram of sling material with a non-tangedsection.

DESCRIPTION

Referring to FIG. 1, a sling 20 in accordance with the present inventioncan be made of one or more materials 22, and includes a first end 24 anda second end 26. The second end 26 is disposed opposite and away fromthe first end 24 along a longitudinal axis 28. The material 22 alsoincludes a first side 30 and a second side 32. The second side 32 isdisposed opposite and away from the first side 30 along a perpendicularaxis 34. The axis 34 is perpendicular to, or substantially perpendicularto, the longitudinal axis 28, and intersects the longitudinal axis 28 atthe midpoint, or substantially the midpoint, of the axis 28. Thelongitudinal axis 28 of the sling 20 may range from about 2.5 cm toabout 45 cm in length, while the perpendicular axis 34 may range fromabout 1.0 cm to about 3.0 cm. The sling is preferably 20 to 30 cm inlength and 1 to 3 cm wide, though larger and smaller slings arecontemplated depending upon the size of the patient and the surface areaof the body part that requires support.

The sling 20 and 21 can be rectangular, as illustrated in FIG. 1, orsubstantially rectangular in shape (e.g., octagonal). Alternatively, thesling may have another shape (e.g., trapezoidal, hexagonal, orelliptical) suitable to its intended placement location within the body.Exemplary shapes are described in U.S. Pat. No. 6,042,534, thedisclosure of which is incorporated herein by reference.

The thickness of the sling material 22 can be uniform over the entirepiece of the material or it can vary at one or more different locations.The thickness of sling material 22 may range from about 0.02 to about0.10 cm, but typically will be about 0.07 cm and have a uniformthickness. The material construction may impact the material thicknessand uniformity; for example, a weave may have thicker regions where thefibers intersect.

The mesh may have any of a number of knits, weaves, or braids, such asthose described in U.S. Pat. Nos. 5,569,273; 5,292,328; 5,002,551;4,838,884; 4,655,221; 4,652,264; 4,633,873; 4,520,821; 4,452,245;4,347,847; 4,193,137; 5,124,136; 3,054,406; and 2,671,444 thedisclosures of which are hereby incorporated by reference.

The mesh material may be fabricated from any of a number ofbiocompatible materials such as nylon, polyethylene, polyester,polypropylene, fluoropolymers, copolymers thereof, combinations thereof,or other suitable synthetic material(s). The material may be, forexample, a synthetic material that is absorbable by the patient's body.Suitable absorbable synthetic materials include polyglycolic acid,polylactic acid, and other suitable absorbable synthetic materials. Themesh material may be fabricated from one or more yarns, which yarns maybe made from one or more materials. The mesh may be produced accordingto numerous fabrication processes, and may be designed to permit rapidtissue revascularization and tissue in-growth by having largeinterstitial spaces. For example, each yarn of the mesh may have voidareas between yarn filaments and the fabrication process may createcrevices. An exemplary weave is a tricot knit with two yarns per needle,as illustrated in FIG. 2. In a preferred embodiment, the mesh iscomposed of polypropylene monofilament yarns.

Absorbable synthetic materials may also be suitable for use inaccordance with the invention. Such absorbable synthetic materialsinclude, for example, polyglycolic acid (PGA), polylactic acid (PLA),and other available absorbable synthetic materials. A suitable PGAmaterial is available under the trade designation DEXON, from TYCO.Other suitable polymeric and non-polymeric synthetic materials may beemployed in accordance with the invention. Exemplary materials as setforth above are found in U.S. Pat. Nos. 6,090,116; 5,569,273; 5,292,328;4,633,873, 4,452,245; 4,347,847; 3,124,136; 3,054,406; and 2,671,444,and Inglesia, C. B. et al. (1997) Int. Urogynecol. J. 8:105-115, theentire disclosures of which are incorporated by reference.

Alternatively, the sling material 22 may be derived from a combinationof mammalian tissue(s) and synthetic material(s). The mammalian tissuesource may be, for example, human, human cadaveric, or tissue-engineeredhuman tissue. The mammalian tissue may alternatively be from an animalsource such as porcine, ovine, bovine, and equine tissue sources. Suchcombinations may also include materials that include both syntheticpolymers and animal cells that are treated so as to cross-link thecollagen or other commonly antigenic fibers of the animal cells. In oneembodiment, at least a portion of the mesh portion of the sling whichcontacts the patient's tissue comprises a synthetic material requiringsmoothness of the tangs.

The tangs (i.e., sharp projections or frayed edges) 40 that form whenthe material 22 is cut, chopped, torn, frayed or otherwise manufacturedmay be located along any edge of the material 22. The tangs 40 aregenerally useful for encouraging tissue growth into the material 22.However, it is found that some tangs 40 may erode the adjacent tissuewhen the sling 20 is inserted into a patient's body. Accordingly, aportion of the tangs 40 located on sides 30 and 32 (e.g., in someembodiments to within about 1 cm to about 5 cm of either side of theperpendicular axis 34) are therefore unformed, smoothed, rounded orremoved to form a non-tanged section 42. By removing these irritativeprojections, which will be in close proximity to the urethra andanterior vaginal wall, the erosion effects are reduced.

With continued reference to FIG. 1, in one version of the sling, a line36 is disposed along the perpendicular axis 34 of a rectangular sling20. The line 36 may be formed by, for example, applying surgical inkalong the perpendicular axis 34 of the material 22. Preferably, theapproximate midpoint of the non-tanged sections 42 of sides 30 and 32intersects with line 36. Thus, line 36 may be employed as a visual guideto evenly align the non-tanged sections 42 with the portion of thepatient's body that the sling 20 is employed to support.

Any process which will smooth, round or remove the tangs 40 to removetheir sharp edges is suitable. For example, the tangs 40 may be heatsmoothed by burning or melting. Such a heat process causes melting ofthe sharp tangs 40 back to the woven knot 44 forming a non-tangedsection 42, as shown best in FIG. 2. The non-tanged section 42 may belocated on both sides 30 and 32, occupying, for example, about 1 to 4 cmon either side of the perpendicular axis 34. The tangs may be removed,for example, along a 5, 6, 7, 8, 9 or 10 cm portion of the side of themesh material.

An exemplary method of making a sling 20 of the invention from amaterial 22, for example, includes manufacturing a sling material 22 andforming a non-tanged section 42 on a portion of a material 22 at sides30 and 32 adjacent the perpendicular axis 34. The sling 20 may be formedfrom the cutting to size of a larger piece of sling material 22. Thetangs 40 on a portion of each side 30 and 32 are unformed, smoothed,rounded or removed (e.g., to the woven knots) to form a non-tangedsection 42. The non-tanged section 42 may span a segment of sides 30 and32 having a length up to about 4 cm, but usually at least about 1 cm,and the segment is preferably centered on the perpendicular axis 34. Inalternative embodiment, the non-tanged section 42 may span a segment ofsides 30 and 32 having a length of 5, 6, 7, 8, 9 or 10 cm. In oneversion of the method, the tangs 40 are smoothed, rounded or removed byexposing the tangs to a source of heat (i.e., by contact or by bringingthe heat source into close proximity to the tangs). In an alternativemethod, a straight blade edge that is heated to a sufficient temperatureto simultaneously cut and smooth the tangs 40 may be employed.

The sling 20 may be surrounded by or enclosed within a sleeve orenvelope as described in the U.S. patent application entitled “Systemfor Implanting an Implant” co-filed with the instant application, whichis hereby incorporated by reference in its entirety. The co-filedapplication also contains methods for installing slings enclosed withinan envelope.

Referring to FIG. 1, the sling 20 may be pre-soaked in a prescribed drugprior to implantation in a patient's body. Exemplary drugs includeneomycin, sulfa drugs, antimicrobials, and antibiotics, generally. Insome embodiments, the hydrophilic material, the drug, or both when usedin combination, release the drug to patient tissues upon contact. Thus,the drugs that are delivered to the patient tissue surfaces whenaccessing and inserting the sling 20 are active upon contact with thepatient's tissue during implantation of the surgical device.

Alternatively, the sling 20 is made of a non-wettable material such as apolypropylene, polyethylene, polyester, polytetrafluoroethylene, TYVEK®,MYLAR®, or co-polymers thereof. Polytetrafluoroethylene ,which issuitable for use in accordance with the present invention, is availablefrom DuPont (Wilmington, Del. under the trade designation TEFLON®). Suchnon-wettable materials do not take up any liquids, for example, drugs insolution. In order to permit drugs to bond or absorb to thesenon-wettable material surfaces, the sling 20 can be treated with asubstance that is wettable such as, for example, a wettable coatingcomposition. The wettable coating composition may be a synthetic coating(e.g., polyvinylperilidone or PVP), a natural coating (e.g., collagen)or a physically absorbent material (e.g., sponge comprising cellulose oropen celled polyurethane). The wettable coating composition may behydrophilic, so as to pick up or absorb hydrophilic drugs. Suitablehydrophilic coatings may be water soluble and include, for example,Hydroplus (Boston Scientific Corp., Natick, Mass.), Hydropass (BostonScientific Corp., Natick, Mass.), hyoscymine sulfate, which is availableunder the trade designation CYTOSPAZ from Polymedica (Woburn, Mass.),and ketrodac fromethamine, which is available under the tradedesignation Toradol from Roche Pharmaceuticals (Nutley, N.J.).Hydrophilic drugs that may be employed in accordance with the inventioninclude oxybutynin chloride, lidocaine, ketorolac, and hyoscyminesulfate, for example.

Similarly, a hydrophobic coating may be employed on one or more surfacesof the sling 20. Suitable hydrophobic coatings include but are notlimited to hydrophobic coatings that may be employed in accordance withthe invention include polytetrafluoroethylene, silicon, and Pyrelene.Such hydrophobic coatings may be used in conjunction with and absorbhydrophobic drugs. Suitable hydrophobic drugs include but are notlimited to suitable hydrophobic drugs include ibuprofen, ketoprofen,diclofenac, and lidocaine in hydrophilic form. Where the bonding betweenthese coatings and drugs is weak, the drug that is absorbed will readilyrelease to be delivered to the surfaces it contacts. Alternatively, astronger bonding affinity may provide a slower timed release of thedrug.

Where the coating applied to the surface of the sling 20 has an ioniccharge, drugs comprising a complementary charge will bond to the coatingwhen the coating and the drug are exposed to one another. The strengthof any bonding will impact how readily the drug is released from thesurface of the sling 20. Where the ionic bonding between the coating andthe drug is weak, the drug will release more readily. In embodimentswhere rapid drug release is desirable, covalent bonding between thesurface coating and the drug should be avoided.

Alternatively, the sling 20 may be coated with hydrophilic coating 75.The sling 20, coated with hydrophilic coating 75, may be dipped into asolution containing a hydrophilic drug just prior to surgery. In anotherembodiment, the hydrophilic coating and the hydrophilic drug are mixedto form a single coating. This coating may be disposed on the surface ofthe sling 20.

Methods of sling delivery and installation, e.g., to treat female stressincontinence include but are not limited to transvaginal, transabdominal(percutaneous), and combined transvaginal and transabdominal procedures.

Variations, modifications, and other implementations of what isdescribed herein will occur to those of ordinary skill in the artwithout departing from the spirit and the scope of the invention.Accordingly, the invention is not to be limited by the precedingillustrative description.

1. A sling for use in a medical application comprising: (a) a first endand a second end, the second end being disposed a distance opposite andaway from the first end along a longitudinal axis; and (b) a first sideand a second side extending between the first and second ends of thesling and each side having at least one tanned section and at least onenon-tanged section; wherein the distance along the longitudinal axisfrom the second end to the first end is from about 2.5 cm to about 45cm. 2-8. (canceled)
 9. The sling of claim 1, wherein the sling comprisesa synthetic material.
 10. The sling of claim 9, wherein the syntheticmaterial is at least one of nylon polyethylene, polyester,polypropylene, fluoropolymers or co-polymers thereof.
 11. (canceled) 12.The sling of claim 1, wherein the sling is enclosed at least partiallyby a sleeve. 13-18. (canceled)
 19. The sling of claim 1, wherein thesecond side is disposed opposite and away from the first side by adistance along an axis that is substantially perpendicular to thelongitudinal axis.
 20. The sling of claim 19, wherein the distance fromthe second side to the first side is from about 1.0 cm to about 3.0 cm.21. The sling of claim 1, wherein at least one non-tanged section iswithin about 1 cm to about 5 cm from a center position relative to thefirst and second ends.
 22. The sling of claim 1, wherein the non-tangedsection of the first side and the second side is from about 5 cm toabout 10 cm in length and is approximately centered relative to thefirst and second ends.
 23. The sling of claim 1, wherein the thicknessof the sling is from about 0.02 cm to about 0.10 cm.
 24. The sling ofclaim 23, wherein the thickness of the sling is about 0.07 cm.
 25. Thesling of claim 1, wherein the sling comprises a bioabsorbable material.26. The sling of claim 25, wherein the bioabsorbable material ispolyglycolic acid (PGA) or polylactic acid (PLA).
 27. The sling of claim1, the sling is pre-soaked.
 28. The sling of claim 1, wherein the slingcomprises a hydrophilic material.
 29. The sling of claim 1, wherein thesling includes a drug that is released to patient tissues.
 30. The slingof claim 1, wherein the sling includes a coating.
 31. The sling of claim30, wherein the coating is a drug-containing coating.
 32. The sling ofclaim 1, wherein the surface of the sling is hydrophilic.
 33. The slingof claim 1, wherein the surface of the sling is hydrophobic.
 34. Thesling of claim 1, wherein the surface of the sling has an ionic charge.